1. Field of the Invention
The present invention relates to an acoustic wave device.
2. Description of Related Art
Acoustic wave devices are used as acoustic wave filters, duplexers, and modules including these, which are included in a mobile communication terminal. Among acoustic wave resonators included in acoustic wave devices are resonators that use waves such as surface acoustic waves (SAW) including leaky waves and love waves, boundary waves, bulk waves, and lamb waves. In a SAW filter, for example, a functional portion that generates an acoustic wave is a region where an interdigital transducer (IDT) electrode is formed.
Here, characteristic deterioration caused by temperature change is one of the problems with acoustic wave devices. Patent Document 1 and Patent Document 2 disclose techniques that improve frequency-temperature characteristics of SAW filters including IDT electrodes.